An Investigation of Neutrino-Driven Convection and the Core Collapse Supernova Mechanism Using Multigroup Neutrino Transport

We investigate neutrino-driven convection in core collapse supernovae and its ramifications for the explosion mechanism. We begin with an “optimistic ” postbounce model in two important respects: (1) we begin with a 15 M ⊙ precollapse model, which is representative of the class of stars with compact iron cores; (2) we implement Newtonian gravity. Our precollapse model is evolved through core collapse and bounce in one dimension using multigroup (neutrino-energy–dependent) flux-limited diffusion (MGFLD) neutrino transport and Newtonian Lagrangian hydrodynamics, providing realistic initial conditions for the postbounce convection and evolution. Our two-dimensional simulation began at 12 ms after bounce and proceeded for 500 ms. We couple two-dimensional (PPM) hydrodynamics to precalculated one-dimensional MGFLD neutrino transport. (The neutrino distributions used for matter heating and deleptonization in our 2D run are obtained from an accompanying 1D simulation. The accuracy of this approximation is assessed.) For the moment we sacrifice dimensionality for realism in other aspects of our neutrino transport. MGFLD is an implementation of neutrino transport that simultaneously (a) is multigroup and (b) simulates with sufficient realism the transport of neutrinos in opaque,